The present invention relates generally to the field of food processing. More particularly, it concerns a new form of tricalcium citrate and methods of its making and use.
In man, calcium is essential for blood clotting, muscle contraction, nerve transmission, and bone and tooth formation and maintenance. The United States recommended daily allowance (USRDA) of calcium for men and women between the ages of 19 and 50 is 1000 mg/day, and is even higher for older prepubescent children, adolescents, and adults over 50. However, it is probable that millions of United States residents fail to ingest recommended levels of calcium. For example, according to the United States National Health and Nutrition Examination Survey, as reported on the World Wide Web at http://www.nichd.nih.gov/milk/whycal/enough_cal.cfm, accessed Apr. 28, 2004, only about half of males ages 9-19 and only about 20% of females ages 9-19 ingest recommended levels of calcium.
The most common dietary source of calcium is dairy products, such as milk, which contains about 0.12% calcium by weight. However, milk competes with (among other beverages) fruit juices, carbonated soft drinks, and non-carbonated soft drinks, which traditionally have little to no calcium content, as beverage choices for United States consumers. Further, people with lactose intolerance often choose to avoid dairy products. Other foods rich in calcium include dark green, leafy vegetables, such as spinach and broccoli, but not all consumers enjoy such vegetables.
In light of these recommendations and observations, there is interest in fortifying foods or beverages with calcium in the form of a calcium-containing compound. Fortifying a food or beverage to level of calcium comparable to that of milk requires consideration of the solubility, bioavailability, and taste profile of the calcium-containing compound.
To insure consistent levels of calcium per serving, the calcium-containing compound desirably is soluble or evenly dispersed through the food or beverage. For clear beverages, it is desirable that the calcium-containing compound provides little if any increase in the opacity of the beverage when dissolved therein. The solubility of the calcium-containing compound in the beverage will depend on the beverage's pH, acid content, protein content, bottling temperature, and storage temperature, and the nature of the calcium-containing compound, among other parameters.
The bioavailability of the calcium-containing compound is the ease (or lack of it) for the calcium therein to reach a site in the body where calcium performs a necessary or useful function. If ingested calcium is not absorbed to an appreciable extent, there is little to no benefit to calcium fortification. In general, bioavailability is positively correlated with solubility, i.e., the more soluble the calcium-containing compound, the greater its bioavailability.
To improve the commercial acceptance of the fortified food or beverage, it is desirable for the calcium-containing compound to have a neutral or a pleasing taste profile. A number of calcium-containing compounds have been found to impart unpleasant flavor or mouth-feel to foods or beverages fortified therewith.
One known fortification approach involves fortification of foods and beverages with calcium salts, including, but not limited to, calcium citrate malate, calcium malate, calcium citrate fumarate, calcium fumarate, calcium lactate, calcium gluconate, calcium carbonate, calcium phosphate, or calcium chloride, among others. Procter & Gamble (Cincinnati, Ohio) is a commercial supplier of at least some of the foregoing calcium salts.
Another technique for fortifying beverages with calcium involves tricalcium citrate as a calcium-containing compound. Tricalcium citrates are commercially available from Jungbunzlauer AG (Basel, Switzerland), Mallinckrodt (St. Louis, Mo.), and Tate & Lyle North America (Decatur, Ill.). Tricalcium citrate has a relatively neutral taste profile and a relatively high bioavailability compared to other calcium-containing compounds. However, the solubility of tricalcium citrate in beverages is relatively low; for example, the solubility is no more than about 0.2 g/L in water at 25° C.
It would be desirable to have calcium-fortified foods and beverages with higher doses of dissolved calcium.